As a combine harvester such as described above, the combine harvester described in Patent Literature 1, for example, is already known. The combine harvester described in Patent Literature 1 includes a reaping device (“mowing blade” in Patent Literature 1) that cuts grain culms in an agricultural field, a harvest frame that receives grain culms cut by a reaping device, a rake-in auger (“auger” in Patent Literature 1) that is disposed within the harvest frame so as to be rotatable about a rotary axis extending in the right/left direction of the harvester body, and that conveys the grain culms inside the harvest frame in a right/left direction of the harvester body and rakes in the grain culms toward the rear of the harvester body, and a feeder (“conveyor” in Patent Literature 1) that is communicatively connected to a rear wall of the harvest frame and that conveys the grain culms raked in by the rake-in auger toward the rear of the harvester body. This combine harvester includes a grain culm sensor that detects the presence of grain culms when coming in contact with the grain culms, on the front edge on the inner surface of the ceiling cover of the threshing chamber. The grain culm sensor is thereby able to detect whether the combine harvester is in a reaping state in which the grain culms are provided into the threshing chamber or is in a non-reaping state.